Merge tag 's390-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Vasily Gorbik:

- Make stack unwinder reliable and suitable for livepatching. Add
unwinder testing module.

- Fixes for CALL_ON_STACK helper used for stack switching.

- Fix unwinding from bpf code.

- Fix getcpu and remove compat support in vdso code.

- Fix address space control registers initialization.

- Save KASLR offset for early dumps.

- Handle new FILTERED_BY_HYPERVISOR reply code in crypto code.

- Minor perf code cleanup and potential memory leak fix.

- Add couple of error messages for corner cases during PCI device
creation.

* tag 's390-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (33 commits)
s390: remove compat vdso code
s390/livepatch: Implement reliable stack tracing for the consistency model
s390/unwind: add stack pointer alignment sanity checks
s390/unwind: filter out unreliable bogus %r14
s390/unwind: start unwinding from reliable state
s390/test_unwind: add program check context tests
s390/test_unwind: add irq context tests
s390/test_unwind: print verbose unwinding results
s390/test_unwind: add CALL_ON_STACK tests
s390: fix register clobbering in CALL_ON_STACK
s390/test_unwind: require that unwinding ended successfully
s390/unwind: add a test for the internal API
s390/unwind: always inline get_stack_pointer
s390/pci: add error message on device number limit
s390/pci: add error message for UID collision
s390/cpum_sf: Check for SDBT and SDB consistency
s390/cpum_sf: Use TEAR_REG macro consistantly
s390/cpum_sf: Remove unnecessary check for pending SDBs
s390/cpum_sf: Replace function name in debug statements
s390/kaslr: store KASLR offset for early dumps
...

arch/s390/Kconfig

···
 	select HAVE_PERF_EVENTS
 	select HAVE_RCU_TABLE_FREE
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_VIRT_CPU_ACCOUNTING
···
 	  handle system-calls from ELF binaries for 31 bit ESA.  This option
 	  (and some other stuff like libraries and such) is needed for
 	  executing 31 bit applications.  It is safe to say "Y".
-
-config COMPAT_VDSO
-	def_bool COMPAT && !CC_IS_CLANG
 
 config SYSVIPC_COMPAT
 	def_bool y if COMPAT && SYSVIPC
···
 
 	  Select this option if you want to run the kernel as a guest under
 	  the KVM hypervisor.
+
+endmenu
+
+menu "Selftests"
+
+config S390_UNWIND_SELFTEST
+	def_tristate n
+	prompt "Test unwind functions"
+	help
+	  This option enables s390 specific stack unwinder testing kernel
+	  module. This option is not useful for distributions or general
+	  kernels, but only for kernel developers working on architecture code.
+
+	  Say N if you are unsure.
 
 endmenu

arch/s390/Makefile

···
 
 vdso_install:
 	$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso64 $@
-	$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso32 $@
 
 archclean:
 	$(Q)$(MAKE) $(clean)=$(boot)

arch/s390/boot/startup.c

···
 		handle_relocs(__kaslr_offset);
 
 	if (__kaslr_offset) {
+		/*
+		 * Save KASLR offset for early dumps, before vmcore_info is set.
+		 * Mark as uneven to distinguish from real vmcore_info pointer.
+		 */
+		S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL;
 		/* Clear non-relocated kernel */
 		if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
 			memset(img, 0, vmlinux.image_size);

arch/s390/include/asm/cpu_mf.h

···
 	return (unsigned long *) ret;
 }
 
-/* Return if the entry in the sample data block table (sdbt)
+/* Return true if the entry in the sample data block table (sdbt)
  * is a link to the next sdbt */
 static inline int is_link_entry(unsigned long *s)
 {

arch/s390/include/asm/perf_event.h

···
 
 #include <linux/perf_event.h>
 #include <linux/device.h>
+#include <asm/stacktrace.h>
 
 /* Per-CPU flags for PMU states */
 #define PMU_F_RESERVED			0x1000
···
 #define SAMPL_DIAG_MODE(hwc)	(SAMPL_FLAGS(hwc) & PERF_CPUM_SF_DIAG_MODE)
 #define SDB_FULL_BLOCKS(hwc)	(SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FULL_BLOCKS)
 #define SAMPLE_FREQ_MODE(hwc)	(SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FREQ_MODE)
+
+#define perf_arch_fetch_caller_regs(regs, __ip) do {			\
+	(regs)->psw.addr = (__ip);					\
+	(regs)->gprs[15] = (unsigned long)__builtin_frame_address(0) -	\
+		offsetof(struct stack_frame, back_chain);		\
+} while (0)
 
 #endif /* _ASM_S390_PERF_EVENT_H */

arch/s390/include/asm/processor.h

···
 /*
  * Function to drop a processor into disabled wait state
  */
-static inline void __noreturn disabled_wait(void)
+static __always_inline void __noreturn disabled_wait(void)
 {
 	psw_t psw;
 

arch/s390/include/asm/stacktrace.h

···
 	return addr >= info->begin && addr + len <= info->end;
 }
 
-static inline unsigned long get_stack_pointer(struct task_struct *task,
-					      struct pt_regs *regs)
+static __always_inline unsigned long get_stack_pointer(struct task_struct *task,
+						       struct pt_regs *regs)
 {
 	if (regs)
 		return (unsigned long) kernel_stack_pointer(regs);
-	if (!task || task == current)
+	if (task == current)
 		return current_stack_pointer();
 	return (unsigned long) task->thread.ksp;
 }
···
 	unsigned long back_chain;
 };
 #endif
+
+/*
+ * Unlike current_stack_pointer() which simply returns current value of %r15
+ * current_frame_address() returns function stack frame address, which matches
+ * %r15 upon function invocation. It may differ from %r15 later if function
+ * allocates stack for local variables or new stack frame to call other
+ * functions.
+ */
+#define current_frame_address()						\
+	((unsigned long)__builtin_frame_address(0) -			\
+	 offsetof(struct stack_frame, back_chain))
 
 #define CALL_ARGS_0()							\
 	register unsigned long r2 asm("2")
···
 
 #define CALL_ON_STACK(fn, stack, nr, args...)				\
 ({									\
+	unsigned long frame = current_frame_address();			\
 	CALL_ARGS_##nr(args);						\
 	unsigned long prev;						\
 									\
 	asm volatile(							\
 		"	la	%[_prev],0(15)\n"			\
-		"	la	15,0(%[_stack])\n"			\
-		"	stg	%[_prev],%[_bc](15)\n"			\
+		"	lg	15,%[_stack]\n"				\
+		"	stg	%[_frame],%[_bc](15)\n"			\
 		"	brasl	14,%[_fn]\n"				\
 		"	la	15,0(%[_prev])\n"			\
 		: [_prev] "=&a" (prev), CALL_FMT_##nr			\
-		  [_stack] "a" (stack),					\
+		  [_stack] "R" (stack),					\
 		  [_bc] "i" (offsetof(struct stack_frame, back_chain)),	\
+		  [_frame] "d" (frame),					\
 		  [_fn] "X" (fn) : CALL_CLOBBER_##nr);			\
 	r2;								\
+})
+
+#define CALL_ON_STACK_NORETURN(fn, stack)				\
+({									\
+	asm volatile(							\
+		"	la	15,0(%[_stack])\n"			\
+		"	xc	%[_bc](8,15),%[_bc](15)\n"		\
+		"	brasl	14,%[_fn]\n"				\
+		::[_bc] "i" (offsetof(struct stack_frame, back_chain)),	\
+		  [_stack] "a" (stack), [_fn] "X" (fn));		\
+	BUG();								\
 })
 
 #endif /* _ASM_S390_STACKTRACE_H */

arch/s390/include/asm/unwind.h

···
 	struct task_struct *task;
 	struct pt_regs *regs;
 	unsigned long sp, ip;
-	bool reuse_sp;
 	int graph_idx;
 	bool reliable;
 	bool error;
···
 static inline void unwind_start(struct unwind_state *state,
 				struct task_struct *task,
 				struct pt_regs *regs,
-				unsigned long sp)
+				unsigned long first_frame)
 {
-	sp = sp ? : get_stack_pointer(task, regs);
-	__unwind_start(state, task, regs, sp);
+	task = task ?: current;
+	first_frame = first_frame ?: get_stack_pointer(task, regs);
+	__unwind_start(state, task, regs, first_frame);
 }
 
 static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)

arch/s390/include/asm/vdso.h

···
 struct vdso_per_cpu_data {
 	__u64 ectg_timer_base;
 	__u64 ectg_user_time;
-	__u32 cpu_nr;
-	__u32 node_id;
+	/*
+	 * Note: node_id and cpu_nr must be at adjacent memory locations.
+	 * VDSO userspace must read both values with a single instruction.
+	 */
+	union {
+		__u64 getcpu_val;
+		struct {
+			__u32 node_id;
+			__u32 cpu_nr;
+		};
+	};
 };
 
 extern struct vdso_data *vdso_data;

arch/s390/kernel/Makefile

···
 
 # vdso
 obj-y				+= vdso64/
-obj-$(CONFIG_COMPAT_VDSO)	+= vdso32/

arch/s390/kernel/asm-offsets.c

···
 	OFFSET(__VDSO_TS_END, vdso_data, ts_end);
 	OFFSET(__VDSO_ECTG_BASE, vdso_per_cpu_data, ectg_timer_base);
 	OFFSET(__VDSO_ECTG_USER, vdso_per_cpu_data, ectg_user_time);
-	OFFSET(__VDSO_CPU_NR, vdso_per_cpu_data, cpu_nr);
-	OFFSET(__VDSO_NODE_ID, vdso_per_cpu_data, node_id);
+	OFFSET(__VDSO_GETCPU_VAL, vdso_per_cpu_data, getcpu_val);
 	BLANK();
 	/* constants used by the vdso */
 	DEFINE(__CLOCK_REALTIME, CLOCK_REALTIME);

arch/s390/kernel/dumpstack.c

···
 		return "unknown";
 	}
 }
+EXPORT_SYMBOL_GPL(stack_type_name);
 
 static inline bool in_stack(unsigned long sp, struct stack_info *info,
 			    enum stack_type type, unsigned long low,
···
 	if (!sp)
 		goto unknown;
 
-	task = task ? : current;
+	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
+	if (sp & 0x7)
+		goto unknown;
 
 	/* Check per-task stack */
 	if (in_task_stack(sp, task, info))
···
 	struct unwind_state state;
 
 	printk("Call Trace:\n");
-	if (!task)
-		task = current;
 	unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
 		printk(state.reliable ? " [<%016lx>] %pSR \n" :
 					"([<%016lx>] %pSR)\n",

arch/s390/kernel/head64.S

···
 #
 	larl	%r14,init_task
 	stg	%r14,__LC_CURRENT
-	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD
+	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD-__PT_SIZE
 #ifdef CONFIG_KASAN
 	brasl	%r14,kasan_early_init
 #endif

arch/s390/kernel/machine_kexec.c

···
 #ifdef CONFIG_CRASH_DUMP
 	int rc;
 
+	preempt_disable();
 	rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image);
+	preempt_enable();
 	return rc == 0;
 #else
 	return false;
···
 	VMCOREINFO_SYMBOL(lowcore_ptr);
 	VMCOREINFO_SYMBOL(high_memory);
 	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
-	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 	vmcoreinfo_append_str("SDMA=%lx\n", __sdma);
 	vmcoreinfo_append_str("EDMA=%lx\n", __edma);
 	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 }
 
 void machine_shutdown(void)

arch/s390/kernel/perf_cpum_sf.c

···
 		}
 	}
 
-	debug_sprintf_event(sfdbg, 5, "%s freed sdbt %p\n", __func__,
-			    sfb->sdbt);
+	debug_sprintf_event(sfdbg, 5, "%s: freed sdbt %#lx\n", __func__,
+			    (unsigned long)sfb->sdbt);
 	memset(sfb, 0, sizeof(*sfb));
 }
 
···
 				   unsigned long num_sdb, gfp_t gfp_flags)
 {
 	int i, rc;
-	unsigned long *new, *tail;
+	unsigned long *new, *tail, *tail_prev = NULL;
 
 	if (!sfb->sdbt || !sfb->tail)
 		return -EINVAL;
···
 	 */
 	if (sfb->sdbt != get_next_sdbt(tail)) {
 		debug_sprintf_event(sfdbg, 3, "%s: "
-				    "sampling buffer is not linked: origin %p"
-				    " tail %p\n", __func__,
-				    (void *)sfb->sdbt, (void *)tail);
+				    "sampling buffer is not linked: origin %#lx"
+				    " tail %#lx\n", __func__,
+				    (unsigned long)sfb->sdbt,
+				    (unsigned long)tail);
 		return -EINVAL;
 	}
 
···
 			sfb->num_sdbt++;
 			/* Link current page to tail of chain */
 			*tail = (unsigned long)(void *) new + 1;
+			tail_prev = tail;
 			tail = new;
 		}
 
···
 		 * issue, a new realloc call (if required) might succeed.
 		 */
 		rc = alloc_sample_data_block(tail, gfp_flags);
-		if (rc)
+		if (rc) {
+			/* Undo last SDBT. An SDBT with no SDB at its first
+			 * entry but with an SDBT entry instead can not be
+			 * handled by the interrupt handler code.
+			 * Avoid this situation.
+			 */
+			if (tail_prev) {
+				sfb->num_sdbt--;
+				free_page((unsigned long) new);
+				tail = tail_prev;
+			}
 			break;
+		}
 		sfb->num_sdb++;
 		tail++;
+		tail_prev = new = NULL;	/* Allocated at least one SBD */
 	}
 
 	/* Link sampling buffer to its origin */
 	*tail = (unsigned long) sfb->sdbt + 1;
 	sfb->tail = tail;
 
-	debug_sprintf_event(sfdbg, 4, "realloc_sampling_buffer: new buffer"
-			    " settings: sdbt %lu sdb %lu\n",
+	debug_sprintf_event(sfdbg, 4, "%s: new buffer"
+			    " settings: sdbt %lu sdb %lu\n", __func__,
 			    sfb->num_sdbt, sfb->num_sdb);
 	return rc;
 }
···
 	rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL);
 	if (rc) {
 		free_sampling_buffer(sfb);
-		debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: "
-			"realloc_sampling_buffer failed with rc %i\n", rc);
+		debug_sprintf_event(sfdbg, 4, "%s: "
+			"realloc_sampling_buffer failed with rc %i\n",
+			__func__, rc);
 	} else
 		debug_sprintf_event(sfdbg, 4,
-			"alloc_sampling_buffer: tear %p dear %p\n",
-			sfb->sdbt, (void *)*sfb->sdbt);
+			"%s: tear %#lx dear %#lx\n", __func__,
+			(unsigned long)sfb->sdbt, (unsigned long)*sfb->sdbt);
 	return rc;
 }
 
···
 	if (num)
 		sfb_account_allocs(num, hwc);
 
-	debug_sprintf_event(sfdbg, 5, "sfb: overflow: overflow %llu ratio %lu"
-			    " num %lu\n", OVERFLOW_REG(hwc), ratio, num);
+	debug_sprintf_event(sfdbg, 5, "%s: overflow %llu ratio %lu num %lu\n",
+			    __func__, OVERFLOW_REG(hwc), ratio, num);
 	OVERFLOW_REG(hwc) = 0;
 }
 
···
 	 */
 	rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC);
 	if (rc)
-		debug_sprintf_event(sfdbg, 5, "sfb: extend: realloc "
-				    "failed with rc %i\n", rc);
+		debug_sprintf_event(sfdbg, 5, "%s: realloc failed with rc %i\n",
+				    __func__, rc);
 
 	if (sfb_has_pending_allocs(sfb, hwc))
-		debug_sprintf_event(sfdbg, 5, "sfb: extend: "
+		debug_sprintf_event(sfdbg, 5, "%s: "
 				    "req %lu alloc %lu remaining %lu\n",
-				    num, sfb->num_sdb - num_old,
+				    __func__, num, sfb->num_sdb - num_old,
 				    sfb_pending_allocs(sfb, hwc));
 }
 
···
 	hwc->sample_period = period;
 	hwc->last_period = hwc->sample_period;
 	local64_set(&hwc->period_left, hwc->sample_period);
-}
-
-static void hw_reset_registers(struct hw_perf_event *hwc,
-			       unsigned long *sdbt_origin)
-{
-	/* (Re)set to first sample-data-block-table */
-	TEAR_REG(hwc) = (unsigned long) sdbt_origin;
 }
 
 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si,
···
 		 */
 		if (sample_rate_to_freq(si, rate) >
 		    sysctl_perf_event_sample_rate) {
-			debug_sprintf_event(sfdbg, 1,
+			debug_sprintf_event(sfdbg, 1, "%s: "
 					    "Sampling rate exceeds maximum "
-					    "perf sample rate\n");
+					    "perf sample rate\n", __func__);
 			rate = 0;
 		}
 	}
···
 	attr->sample_period = rate;
 	SAMPL_RATE(hwc) = rate;
 	hw_init_period(hwc, SAMPL_RATE(hwc));
-	debug_sprintf_event(sfdbg, 4, "__hw_perf_event_init_rate:"
-			    "cpu:%d period:%#llx freq:%d,%#lx\n", event->cpu,
-			    event->attr.sample_period, event->attr.freq,
-			    SAMPLE_FREQ_MODE(hwc));
+	debug_sprintf_event(sfdbg, 4, "%s: cpu %d period %#llx freq %d,%#lx\n",
+			    __func__, event->cpu, event->attr.sample_period,
+			    event->attr.freq, SAMPLE_FREQ_MODE(hwc));
 	return 0;
 }
 
···
 			 * buffer extents
 			 */
 			sfb_account_overflows(cpuhw, hwc);
-			if (sfb_has_pending_allocs(&cpuhw->sfb, hwc))
-				extend_sampling_buffer(&cpuhw->sfb, hwc);
+			extend_sampling_buffer(&cpuhw->sfb, hwc);
 		}
 		/* Rate may be adjusted with ioctl() */
 		cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw);
···
 	/* Load current program parameter */
 	lpp(&S390_lowcore.lpp);
 
-	debug_sprintf_event(sfdbg, 6, "pmu_enable: es %i cs %i ed %i cd %i "
-			    "interval %#lx tear %p dear %p\n",
+	debug_sprintf_event(sfdbg, 6, "%s: es %i cs %i ed %i cd %i "
+			    "interval %#lx tear %#lx dear %#lx\n", __func__,
 			    cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed,
 			    cpuhw->lsctl.cd, cpuhw->lsctl.interval,
-			    (void *) cpuhw->lsctl.tear,
-			    (void *) cpuhw->lsctl.dear);
+			    cpuhw->lsctl.tear, cpuhw->lsctl.dear);
 }
 
 static void cpumsf_pmu_disable(struct pmu *pmu)
···
 			cpuhw->lsctl.dear = si.dear;
 		}
 	} else
-		debug_sprintf_event(sfdbg, 3, "cpumsf_pmu_disable: "
-				    "qsi() failed with err %i\n", err);
+		debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n",
+				    __func__, err);
 
 	cpuhw->flags &= ~PMU_F_ENABLED;
 }
···
 			sampl_overflow += te->overflow;
 
 		/* Timestamps are valid for full sample-data-blocks only */
-		debug_sprintf_event(sfdbg, 6, "%s: sdbt %p "
+		debug_sprintf_event(sfdbg, 6, "%s: sdbt %#lx "
 				    "overflow %llu timestamp %#llx\n",
-				    __func__, sdbt, te->overflow,
+				    __func__, (unsigned long)sdbt, te->overflow,
 				    (te->f) ? trailer_timestamp(te) : 0ULL);
 
 		/* Collect all samples from a single sample-data-block and
···
 						 sampl_overflow, 1 + num_sdb);
 	if (sampl_overflow || event_overflow)
 		debug_sprintf_event(sfdbg, 4, "%s: "
-				    "overflow stats: sample %llu event %llu\n",
-				    __func__, sampl_overflow, event_overflow);
+				    "overflows: sample %llu event %llu"
+				    " total %llu num_sdb %llu\n",
+				    __func__, sampl_overflow, event_overflow,
+				    OVERFLOW_REG(hwc), num_sdb);
 }
 
 #define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb)
···
 	cpuhw->lsctl.tear = base + offset * sizeof(unsigned long);
 	cpuhw->lsctl.dear = aux->sdb_index[head];
 
-	debug_sprintf_event(sfdbg, 6, "aux_output_begin: "
+	debug_sprintf_event(sfdbg, 6, "%s: "
 			    "head->alert_mark->empty_mark (num_alert, range)"
 			    "[%#lx -> %#lx -> %#lx] (%#lx, %#lx) "
-			    "tear index %#lx, tear %#lx dear %#lx\n",
+			    "tear index %#lx, tear %#lx dear %#lx\n", __func__,
 			    aux->head, aux->alert_mark, aux->empty_mark,
 			    AUX_SDB_NUM_ALERT(aux), range,
 			    head / CPUM_SF_SDB_PER_TABLE,
···
 			pr_err("The AUX buffer with %lu pages for the "
 			       "diagnostic-sampling mode is full\n",
 				num_sdb);
-			debug_sprintf_event(sfdbg, 1, "AUX buffer used up\n");
+			debug_sprintf_event(sfdbg, 1,
+					    "%s: AUX buffer used up\n",
+					    __func__);
 			break;
 		}
 		if (WARN_ON_ONCE(!aux))
···
 			perf_aux_output_end(&cpuhw->handle, size);
 			pr_err("Sample data caused the AUX buffer with %lu "
 			       "pages to overflow\n", num_sdb);
-			debug_sprintf_event(sfdbg, 1, "head %#lx range %#lx "
-					    "overflow %#llx\n",
+			debug_sprintf_event(sfdbg, 1, "%s: head %#lx range %#lx "
+					    "overflow %#llx\n", __func__,
 					    aux->head, range, overflow);
 		} else {
 			size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT;
 			perf_aux_output_end(&cpuhw->handle, size);
-			debug_sprintf_event(sfdbg, 6, "head %#lx alert %#lx "
+			debug_sprintf_event(sfdbg, 6, "%s: head %#lx alert %#lx "
 					    "already full, try another\n",
+					    __func__,
 					    aux->head, aux->alert_mark);
 		}
 	}
 
 	if (done)
-		debug_sprintf_event(sfdbg, 6, "aux_reset_buffer: "
+		debug_sprintf_event(sfdbg, 6, "%s: aux_reset_buffer "
 				    "[%#lx -> %#lx -> %#lx] (%#lx, %#lx)\n",
-				    aux->head, aux->alert_mark, aux->empty_mark,
-				    AUX_SDB_NUM_ALERT(aux), range);
+				    __func__, aux->head, aux->alert_mark,
+				    aux->empty_mark, AUX_SDB_NUM_ALERT(aux),
+				    range);
 }
 
 /*
···
 	kfree(aux->sdb_index);
 	kfree(aux);
 
-	debug_sprintf_event(sfdbg, 4, "aux_buffer_free: free "
-			    "%lu SDBTs\n", num_sdbt);
+	debug_sprintf_event(sfdbg, 4, "%s: free "
+			    "%lu SDBTs\n", __func__, num_sdbt);
 }
 
 static void aux_sdb_init(unsigned long sdb)
···
 	 */
 	aux->empty_mark = sfb->num_sdb - 1;
 
-	debug_sprintf_event(sfdbg, 4, "aux_buffer_setup: setup %lu SDBTs"
-			    " and %lu SDBs\n",
-			    sfb->num_sdbt, sfb->num_sdb);
+	debug_sprintf_event(sfdbg, 4, "%s: setup %lu SDBTs and %lu SDBs\n",
+			    __func__, sfb->num_sdbt, sfb->num_sdb);
 
 	return aux;
 
···
 	event->attr.sample_period = rate;
 	SAMPL_RATE(&event->hw) = rate;
 	hw_init_period(&event->hw, SAMPL_RATE(&event->hw));
-	debug_sprintf_event(sfdbg, 4, "cpumsf_pmu_check_period:"
-			    "cpu:%d value:%#llx period:%#llx freq:%d\n",
-			    event->cpu, value,
+	debug_sprintf_event(sfdbg, 4, "%s:"
+			    " cpu %d value %#llx period %#llx freq %d\n",
+			    __func__, event->cpu, value,
 			    event->attr.sample_period, do_freq);
 	return 0;
 }
···
 	if (!SAMPL_DIAG_MODE(&event->hw)) {
 		cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt;
 		cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt;
-		hw_reset_registers(&event->hw, cpuhw->sfb.sdbt);
+		TEAR_REG(&event->hw) = (unsigned long) cpuhw->sfb.sdbt;
 	}
 
 	/* Ensure sampling functions are in the disabled state.  If disabled,
···
 
 	/* Report measurement alerts only for non-PRA codes */
 	if (alert != CPU_MF_INT_SF_PRA)
-		debug_sprintf_event(sfdbg, 6, "measurement alert: %#x\n",
+		debug_sprintf_event(sfdbg, 6, "%s: alert %#x\n", __func__,
 				    alert);
 
 	/* Sampling authorization change request */

arch/s390/kernel/setup.c

···
 
 void __init arch_call_rest_init(void)
 {
-	struct stack_frame *frame;
 	unsigned long stack;
 
 	stack = stack_alloc();
···
 	set_task_stack_end_magic(current);
 	stack += STACK_INIT_OFFSET;
 	S390_lowcore.kernel_stack = stack;
-	frame = (struct stack_frame *) stack;
-	memset(frame, 0, sizeof(*frame));
-	/* Branch to rest_init on the new stack, never returns */
-	asm volatile(
-		"	la	15,0(%[_frame])\n"
-		"	jg	rest_init\n"
-		: : [_frame] "a" (frame));
+	CALL_ON_STACK_NORETURN(rest_init, stack);
 }
 
 static void __init setup_lowcore_dat_off(void)

arch/s390/kernel/smp.c

···
 	lc->spinlock_index = 0;
 	lc->percpu_offset = __per_cpu_offset[cpu];
 	lc->kernel_asce = S390_lowcore.kernel_asce;
+	lc->user_asce = S390_lowcore.kernel_asce;
 	lc->machine_flags = S390_lowcore.machine_flags;
 	lc->user_timer = lc->system_timer =
 		lc->steal_timer = lc->avg_steal_timer = 0;
 	__ctl_store(lc->cregs_save_area, 0, 15);
+	lc->cregs_save_area[1] = lc->kernel_asce;
+	lc->cregs_save_area[7] = lc->vdso_asce;
 	save_access_regs((unsigned int *) lc->access_regs_save_area);
 	memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 	       sizeof(lc->stfle_fac_list));
···
 
 	S390_lowcore.last_update_clock = get_tod_clock();
 	restore_access_regs(S390_lowcore.access_regs_save_area);
+	set_cpu_flag(CIF_ASCE_PRIMARY);
+	set_cpu_flag(CIF_ASCE_SECONDARY);
 	cpu_init();
 	preempt_disable();
 	init_cpu_timer();
···
 	S390_lowcore.restart_source = -1UL;
 	__ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
-	CALL_ON_STACK(smp_init_secondary, S390_lowcore.kernel_stack, 0);
+	CALL_ON_STACK_NORETURN(smp_init_secondary, S390_lowcore.kernel_stack);
 }
 
 /* Upping and downing of CPUs */

arch/s390/kernel/stacktrace.c

···
 #include <linux/stacktrace.h>
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
+#include <asm/kprobes.h>
 
 void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 		     struct task_struct *task, struct pt_regs *regs)
···
 		if (!addr || !consume_entry(cookie, addr, false))
 			break;
 	}
+}
+
+/*
+ * This function returns an error if it detects any unreliable features of the
+ * stack.  Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
+{
+	struct unwind_state state;
+	unsigned long addr;
+
+	unwind_for_each_frame(&state, task, NULL, 0) {
+		if (state.stack_info.type != STACK_TYPE_TASK)
+			return -EINVAL;
+
+		if (state.regs)
+			return -EINVAL;
+
+		addr = unwind_get_return_address(&state);
+		if (!addr)
+			return -EINVAL;
+
+#ifdef CONFIG_KPROBES
+		/*
+		 * Mark stacktraces with kretprobed functions on them
+		 * as unreliable.
+		 */
+		if (state.ip == (unsigned long)kretprobe_trampoline)
+			return -EINVAL;
+#endif
+
+		if (!consume_entry(cookie, addr, false))
+			return -EINVAL;
+	}
+
+	/* Check for stack corruption */
+	if (unwind_error(&state))
+		return -EINVAL;
+	return 0;
 }

arch/s390/kernel/unwind_bc.c

···
 	return true;
 }
 
+static inline bool is_task_pt_regs(struct unwind_state *state,
+				   struct pt_regs *regs)
+{
+	return task_pt_regs(state->task) == regs;
+}
+
 bool unwind_next_frame(struct unwind_state *state)
 {
 	struct stack_info *info = &state->stack_info;
···
 
 	regs = state->regs;
 	if (unlikely(regs)) {
-		if (state->reuse_sp) {
-			sp = state->sp;
-			state->reuse_sp = false;
-		} else {
-			sp = READ_ONCE_NOCHECK(regs->gprs[15]);
-			if (unlikely(outside_of_stack(state, sp))) {
-				if (!update_stack_info(state, sp))
-					goto out_err;
-			}
-		}
+		sp = state->sp;
 		sf = (struct stack_frame *) sp;
 		ip = READ_ONCE_NOCHECK(sf->gprs[8]);
 		reliable = false;
 		regs = NULL;
+		if (!__kernel_text_address(ip)) {
+			/* skip bogus %r14 */
+			state->regs = NULL;
+			return unwind_next_frame(state);
+		}
 	} else {
 		sf = (struct stack_frame *) state->sp;
 		sp = READ_ONCE_NOCHECK(sf->back_chain);
···
 			/* No back-chain, look for a pt_regs structure */
 			sp = state->sp + STACK_FRAME_OVERHEAD;
 			if (!on_stack(info, sp, sizeof(struct pt_regs)))
-				goto out_stop;
+				goto out_err;
 			regs = (struct pt_regs *) sp;
-			if (READ_ONCE_NOCHECK(regs->psw.mask) & PSW_MASK_PSTATE)
+			if (is_task_pt_regs(state, regs))
 				goto out_stop;
 			ip = READ_ONCE_NOCHECK(regs->psw.addr);
+			sp = READ_ONCE_NOCHECK(regs->gprs[15]);
+			if (unlikely(outside_of_stack(state, sp))) {
+				if (!update_stack_info(state, sp))
+					goto out_err;
+			}
 			reliable = true;
 		}
 	}
+
+	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
+	if (sp & 0x7)
+		goto out_err;
 
 	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, (void *) sp);
 
···
 EXPORT_SYMBOL_GPL(unwind_next_frame);
 
 void __unwind_start(struct unwind_state *state, struct task_struct *task,
-		    struct pt_regs *regs, unsigned long sp)
+		    struct pt_regs *regs, unsigned long first_frame)
 {
 	struct stack_info *info = &state->stack_info;
-	unsigned long *mask = &state->stack_mask;
-	bool reliable, reuse_sp;
 	struct stack_frame *sf;
-	unsigned long ip;
+	unsigned long ip, sp;
 
 	memset(state, 0, sizeof(*state));
 	state->task = task;
···
 		return;
 	}
 
+	/* Get the instruction pointer from pt_regs or the stack frame */
+	if (regs) {
+		ip = regs->psw.addr;
+		sp = regs->gprs[15];
+	} else if (task == current) {
+		sp = current_frame_address();
+	} else {
+		sp = task->thread.ksp;
+	}
+
 	/* Get current stack pointer and initialize stack info */
-	if (get_stack_info(sp, task, info, mask) != 0 ||
-	    !on_stack(info, sp, sizeof(struct stack_frame))) {
+	if (!update_stack_info(state, sp)) {
 		/* Something is wrong with the stack pointer */
 		info->type = STACK_TYPE_UNKNOWN;
 		state->error = true;
 		return;
 	}
 
-	/* Get the instruction pointer from pt_regs or the stack frame */
-	if (regs) {
-		ip = READ_ONCE_NOCHECK(regs->psw.addr);
-		reliable = true;
-		reuse_sp = true;
-	} else {
-		sf = (struct stack_frame *) sp;
+	if (!regs) {
+		/* Stack frame is within valid stack */
+		sf = (struct stack_frame *)sp;
 		ip = READ_ONCE_NOCHECK(sf->gprs[8]);
-		reliable = false;
-		reuse_sp = false;
 	}
 
 	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, NULL);
···
 	/* Update unwind state */
 	state->sp = sp;
 	state->ip = ip;
-	state->reliable = reliable;
-	state->reuse_sp = reuse_sp;
+	state->reliable = true;
+
+	if (!first_frame)
+		return;
+	/* Skip through the call chain to the specified starting frame */
+	while (!unwind_done(state)) {
+		if (on_stack(&state->stack_info, first_frame, sizeof(struct stack_frame))) {
+			if (state->sp >= first_frame)
+				break;
+		}
+		unwind_next_frame(state);
+	}
 }
 EXPORT_SYMBOL_GPL(__unwind_start);

arch/s390/kernel/vdso.c

···
 #include <asm/vdso.h>
 #include <asm/facility.h>
 
-#ifdef CONFIG_COMPAT_VDSO
-extern char vdso32_start, vdso32_end;
-static void *vdso32_kbase = &vdso32_start;
-static unsigned int vdso32_pages;
-static struct page **vdso32_pagelist;
-#endif
-
 extern char vdso64_start, vdso64_end;
 static void *vdso64_kbase = &vdso64_start;
 static unsigned int vdso64_pages;
···
 
 	vdso_pagelist = vdso64_pagelist;
 	vdso_pages = vdso64_pages;
-#ifdef CONFIG_COMPAT_VDSO
-	if (vma->vm_mm->context.compat_mm) {
-		vdso_pagelist = vdso32_pagelist;
-		vdso_pages = vdso32_pages;
-	}
-#endif
 
 	if (vmf->pgoff >= vdso_pages)
 		return VM_FAULT_SIGBUS;
···
 	unsigned long vdso_pages;
 
 	vdso_pages = vdso64_pages;
-#ifdef CONFIG_COMPAT_VDSO
-	if (vma->vm_mm->context.compat_mm)
-		vdso_pages = vdso32_pages;
-#endif
 
 	if ((vdso_pages << PAGE_SHIFT) != vma->vm_end - vma->vm_start)
 		return -EINVAL;
···
 	if (!vdso_enabled)
 		return 0;
 
+	if (is_compat_task())
+		return 0;
+
 	vdso_pages = vdso64_pages;
-#ifdef CONFIG_COMPAT_VDSO
-	mm->context.compat_mm = is_compat_task();
-	if (mm->context.compat_mm)
-		vdso_pages = vdso32_pages;
-#endif
 	/*
 	 * vDSO has a problem and was disabled, just don't "enable" it for
 	 * the process
···
 	int i;
 
 	vdso_init_data(vdso_data);
-#ifdef CONFIG_COMPAT_VDSO
-	/* Calculate the size of the 32 bit vDSO */
-	vdso32_pages = ((&vdso32_end - &vdso32_start
-			 + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
-
-	/* Make sure pages are in the correct state */
-	vdso32_pagelist = kcalloc(vdso32_pages + 1, sizeof(struct page *),
-				  GFP_KERNEL);
-	BUG_ON(vdso32_pagelist == NULL);
-	for (i = 0; i < vdso32_pages - 1; i++) {
-		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
-		get_page(pg);
-		vdso32_pagelist[i] = pg;
-	}
-	vdso32_pagelist[vdso32_pages - 1] = virt_to_page(vdso_data);
-	vdso32_pagelist[vdso32_pages] = NULL;
-#endif
 
 	/* Calculate the size of the 64 bit vDSO */
 	vdso64_pages = ((&vdso64_end - &vdso64_start

arch/s390/kernel/vdso32/.gitignore

···
-vdso32.lds

arch/s390/kernel/vdso32/Makefile

···
-# SPDX-License-Identifier: GPL-2.0
-# List of files in the vdso, has to be asm only for now
-
-KCOV_INSTRUMENT := n
-
-obj-vdso32 = gettimeofday.o clock_getres.o clock_gettime.o note.o getcpu.o
-
-# Build rules
-
-targets := $(obj-vdso32) vdso32.so vdso32.so.dbg
-obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
-
-KBUILD_AFLAGS += -DBUILD_VDSO
-KBUILD_CFLAGS += -DBUILD_VDSO
-
-KBUILD_AFLAGS_31 := $(filter-out -m64,$(KBUILD_AFLAGS))
-KBUILD_AFLAGS_31 += -m31 -s
-
-KBUILD_CFLAGS_31 := $(filter-out -m64,$(KBUILD_CFLAGS))
-KBUILD_CFLAGS_31 += -m31 -fPIC -shared -fno-common -fno-builtin
-KBUILD_CFLAGS_31 += -nostdlib -Wl,-soname=linux-vdso32.so.1 \
-		    -Wl,--hash-style=both
-
-$(targets:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_31)
-$(targets:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_31)
-
-obj-y += vdso32_wrapper.o
-extra-y += vdso32.lds
-CPPFLAGS_vdso32.lds += -P -C -U$(ARCH)
-
-# Disable gcov profiling, ubsan and kasan for VDSO code
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KASAN_SANITIZE := n
-
-# Force dependency (incbin is bad)
-$(obj)/vdso32_wrapper.o : $(obj)/vdso32.so
-
-# link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) FORCE
-	$(call if_changed,vdso32ld)
-
-# strip rule for the .so file
-$(obj)/%.so: OBJCOPYFLAGS := -S
-$(obj)/%.so: $(obj)/%.so.dbg FORCE
-	$(call if_changed,objcopy)
-
-# assembly rules for the .S files
-$(obj-vdso32): %.o: %.S FORCE
-	$(call if_changed_dep,vdso32as)
-
-# actual build commands
-quiet_cmd_vdso32ld = VDSO32L $@
-      cmd_vdso32ld = $(CC) $(c_flags) -Wl,-T $(filter %.lds %.o,$^) -o $@
-quiet_cmd_vdso32as = VDSO32A $@
-      cmd_vdso32as = $(CC) $(a_flags) -c -o $@ $<
-
-# install commands for the unstripped file
-quiet_cmd_vdso_install = INSTALL $@
-      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
-
-vdso32.so: $(obj)/vdso32.so.dbg
-	@mkdir -p $(MODLIB)/vdso
-	$(call cmd,vdso_install)
-
-vdso_install: vdso32.so

arch/s390/kernel/vdso32/clock_getres.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of clock_getres() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2008
- *  Author(s): Martin Schwidefsky ([e-mail])
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-#include <asm/dwarf.h>
-
-	.text
-	.align 4
-	.globl __kernel_clock_getres
-	.type  __kernel_clock_getres,@function
-__kernel_clock_getres:
-	CFI_STARTPROC
-	basr	%r1,0
-	la	%r1,4f-.(%r1)
-	chi	%r2,__CLOCK_REALTIME
-	je	0f
-	chi	%r2,__CLOCK_MONOTONIC
-	je	0f
-	la	%r1,5f-4f(%r1)
-	chi	%r2,__CLOCK_REALTIME_COARSE
-	je	0f
-	chi	%r2,__CLOCK_MONOTONIC_COARSE
-	jne	3f
-0:	ltr	%r3,%r3
-	jz	2f				/* res == NULL */
-1:	l	%r0,0(%r1)
-	xc	0(4,%r3),0(%r3)			/* set tp->tv_sec to zero */
-	st	%r0,4(%r3)			/* store tp->tv_usec */
-2:	lhi	%r2,0
-	br	%r14
-3:	lhi	%r1,__NR_clock_getres		/* fallback to svc */
-	svc	0
-	br	%r14
-	CFI_ENDPROC
-4:	.long	__CLOCK_REALTIME_RES
-5:	.long	__CLOCK_COARSE_RES
-	.size	__kernel_clock_getres,.-__kernel_clock_getres

arch/s390/kernel/vdso32/clock_gettime.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of clock_gettime() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2008
- *  Author(s): Martin Schwidefsky ([e-mail])
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-#include <asm/dwarf.h>
-#include <asm/ptrace.h>
-
-	.text
-	.align 4
-	.globl __kernel_clock_gettime
-	.type  __kernel_clock_gettime,@function
-__kernel_clock_gettime:
-	CFI_STARTPROC
-	ahi	%r15,-16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD+16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-	basr	%r5,0
-0:	al	%r5,21f-0b(%r5)			/* get &_vdso_data */
-	chi	%r2,__CLOCK_REALTIME_COARSE
-	je	10f
-	chi	%r2,__CLOCK_REALTIME
-	je	11f
-	chi	%r2,__CLOCK_MONOTONIC_COARSE
-	je	9f
-	chi	%r2,__CLOCK_MONOTONIC
-	jne	19f
-
-	/* CLOCK_MONOTONIC */
-1:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	1b
-	stcke	0(%r15)				/* Store TOD clock */
-	lm	%r0,%r1,1(%r15)
-	s	%r0,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
-	sl	%r1,__VDSO_XTIME_STAMP+4(%r5)
-	brc	3,2f
-	ahi	%r0,-1
-2:	ms	%r0,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
-	lr	%r2,%r0
-	l	%r0,__VDSO_TK_MULT(%r5)
-	ltr	%r1,%r1
-	mr	%r0,%r0
-	jnm	3f
-	a	%r0,__VDSO_TK_MULT(%r5)
-3:	alr	%r0,%r2
-	al	%r0,__VDSO_WTOM_NSEC(%r5)
-	al	%r1,__VDSO_WTOM_NSEC+4(%r5)
-	brc	12,5f
-	ahi	%r0,1
-5:	l	%r2,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
-	srdl	%r0,0(%r2)			/*  >> tk->shift */
-	l	%r2,__VDSO_WTOM_SEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	1b
-	basr	%r5,0
-6:	ltr	%r0,%r0
-	jnz	7f
-	cl	%r1,20f-6b(%r5)
-	jl	8f
-7:	ahi	%r2,1
-	sl	%r1,20f-6b(%r5)
-	brc	3,6b
-	ahi	%r0,-1
-	j	6b
-8:	st	%r2,0(%r3)			/* store tp->tv_sec */
-	st	%r1,4(%r3)			/* store tp->tv_nsec */
-	lhi	%r2,0
-	ahi	%r15,16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD
-	CFI_RESTORE 15
-	br	%r14
-
-	/* CLOCK_MONOTONIC_COARSE */
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD+16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-9:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	9b
-	l	%r2,__VDSO_WTOM_CRS_SEC+4(%r5)
-	l	%r1,__VDSO_WTOM_CRS_NSEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	9b
-	j	8b
-
-	/* CLOCK_REALTIME_COARSE */
-10:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	10b
-	l	%r2,__VDSO_XTIME_CRS_SEC+4(%r5)
-	l	%r1,__VDSO_XTIME_CRS_NSEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	10b
-	j	17f
-
-	/* CLOCK_REALTIME */
-11:	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	11b
-	stcke	0(%r15)				/* Store TOD clock */
-	lm	%r0,%r1,__VDSO_TS_END(%r5)	/* TOD steering end time */
-	s	%r0,1(%r15)			/* no - ts_steering_end */
-	sl	%r1,5(%r15)
-	brc	3,22f
-	ahi	%r0,-1
-22:	ltr	%r0,%r0				/* past end of steering? */
-	jm	24f
-	srdl	%r0,15				/* 1 per 2^16 */
-	tm	__VDSO_TS_DIR+3(%r5),0x01	/* steering direction? */
-	jz	23f
-	lcr	%r0,%r0				/* negative TOD offset */
-	lcr	%r1,%r1
-	je	23f
-	ahi	%r0,-1
-23:	a	%r0,1(%r15)			/* add TOD timestamp */
-	al	%r1,5(%r15)
-	brc	12,25f
-	ahi	%r0,1
-	j	25f
-24:	lm	%r0,%r1,1(%r15)			/* load TOD timestamp */
-25:	s	%r0,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
-	sl	%r1,__VDSO_XTIME_STAMP+4(%r5)
-	brc	3,12f
-	ahi	%r0,-1
-12:	ms	%r0,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
-	lr	%r2,%r0
-	l	%r0,__VDSO_TK_MULT(%r5)
-	ltr	%r1,%r1
-	mr	%r0,%r0
-	jnm	13f
-	a	%r0,__VDSO_TK_MULT(%r5)
-13:	alr	%r0,%r2
-	al	%r0,__VDSO_XTIME_NSEC(%r5)	/*  + tk->xtime_nsec */
-	al	%r1,__VDSO_XTIME_NSEC+4(%r5)
-	brc	12,14f
-	ahi	%r0,1
-14:	l	%r2,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
-	srdl	%r0,0(%r2)			/*  >> tk->shift */
-	l	%r2,__VDSO_XTIME_SEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	11b
-	basr	%r5,0
-15:	ltr	%r0,%r0
-	jnz	16f
-	cl	%r1,20f-15b(%r5)
-	jl	17f
-16:	ahi	%r2,1
-	sl	%r1,20f-15b(%r5)
-	brc	3,15b
-	ahi	%r0,-1
-	j	15b
-17:	st	%r2,0(%r3)			/* store tp->tv_sec */
-	st	%r1,4(%r3)			/* store tp->tv_nsec */
-	lhi	%r2,0
-	ahi	%r15,16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD
-	CFI_RESTORE 15
-	br	%r14
-
-	/* Fallback to system call */
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD+16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-19:	lhi	%r1,__NR_clock_gettime
-	svc	0
-	ahi	%r15,16
-	CFI_DEF_CFA_OFFSET STACK_FRAME_OVERHEAD
-	CFI_RESTORE 15
-	br	%r14
-	CFI_ENDPROC
-
-20:	.long	1000000000
-21:	.long	_vdso_data - 0b
-	.size	__kernel_clock_gettime,.-__kernel_clock_gettime

arch/s390/kernel/vdso32/getcpu.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of getcpu() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2016
- *  Author(s): Martin Schwidefsky <[e-mail]>
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/dwarf.h>
-
-	.text
-	.align 4
-	.globl __kernel_getcpu
-	.type  __kernel_getcpu,@function
-__kernel_getcpu:
-	CFI_STARTPROC
-	la	%r4,0
-	sacf	256
-	l	%r5,__VDSO_CPU_NR(%r4)
-	l	%r4,__VDSO_NODE_ID(%r4)
-	sacf	0
-	ltr	%r2,%r2
-	jz	2f
-	st	%r5,0(%r2)
-2:	ltr	%r3,%r3
-	jz	3f
-	st	%r4,0(%r3)
-3:	lhi	%r2,0
-	br	%r14
-	CFI_ENDPROC
-	.size	__kernel_getcpu,.-__kernel_getcpu

arch/s390/kernel/vdso32/gettimeofday.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Userland implementation of gettimeofday() for 32 bits processes in a
- * s390 kernel for use in the vDSO
- *
- *  Copyright IBM Corp. 2008
- *  Author(s): Martin Schwidefsky ([e-mail])
- */
-#include <asm/vdso.h>
-#include <asm/asm-offsets.h>
-#include <asm/unistd.h>
-#include <asm/dwarf.h>
-#include <asm/ptrace.h>
-
-	.text
-	.align 4
-	.globl __kernel_gettimeofday
-	.type  __kernel_gettimeofday,@function
-__kernel_gettimeofday:
-	CFI_STARTPROC
-	ahi	%r15,-16
-	CFI_ADJUST_CFA_OFFSET 16
-	CFI_VAL_OFFSET 15, -STACK_FRAME_OVERHEAD
-	basr	%r5,0
-0:	al	%r5,13f-0b(%r5)			/* get &_vdso_data */
-1:	ltr	%r3,%r3				/* check if tz is NULL */
-	je	2f
-	mvc	0(8,%r3),__VDSO_TIMEZONE(%r5)
-2:	ltr	%r2,%r2				/* check if tv is NULL */
-	je	10f
-	l	%r4,__VDSO_UPD_COUNT+4(%r5)	/* load update counter */
-	tml	%r4,0x0001			/* pending update ? loop */
-	jnz	1b
-	stcke	0(%r15)				/* Store TOD clock */
-	lm	%r0,%r1,__VDSO_TS_END(%r5)	/* TOD steering end time */
-	s	%r0,1(%r15)
-	sl	%r1,5(%r15)
-	brc	3,14f
-	ahi	%r0,-1
-14:	ltr	%r0,%r0				/* past end of steering? */
-	jm	16f
-	srdl	%r0,15				/* 1 per 2^16 */
-	tm	__VDSO_TS_DIR+3(%r5),0x01	/* steering direction? */
-	jz	15f
-	lcr	%r0,%r0				/* negative TOD offset */
-	lcr	%r1,%r1
-	je	15f
-	ahi	%r0,-1
-15:	a	%r0,1(%r15)			/* add TOD timestamp */
-	al	%r1,5(%r15)
-	brc	12,17f
-	ahi	%r0,1
-	j	17f
-16:	lm	%r0,%r1,1(%r15)			/* load TOD timestamp */
-17:	s	%r0,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
-	sl	%r1,__VDSO_XTIME_STAMP+4(%r5)
-	brc	3,3f
-	ahi	%r0,-1
-3:	ms	%r0,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
-	st	%r0,0(%r15)
-	l	%r0,__VDSO_TK_MULT(%r5)
-	ltr	%r1,%r1
-	mr	%r0,%r0
-	jnm	4f
-	a	%r0,__VDSO_TK_MULT(%r5)
-4:	al	%r0,0(%r15)
-	al	%r0,__VDSO_XTIME_NSEC(%r5)	/*  + xtime */
-	al	%r1,__VDSO_XTIME_NSEC+4(%r5)
-	brc	12,5f
-	ahi	%r0,1
-5:	mvc	0(4,%r15),__VDSO_XTIME_SEC+4(%r5)
-	cl	%r4,__VDSO_UPD_COUNT+4(%r5)	/* check update counter */
-	jne	1b
-	l	%r4,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
-	srdl	%r0,0(%r4)			/*  >> tk->shift */
-	l	%r4,0(%r15)			/* get tv_sec from stack */
-	basr	%r5,0
-6:	ltr	%r0,%r0
-	jnz	7f
-	cl	%r1,11f-6b(%r5)
-	jl	8f
-7:	ahi	%r4,1
-	sl	%r1,11f-6b(%r5)
-	brc	3,6b
-	ahi	%r0,-1
-	j	6b
-8:	st	%r4,0(%r2)			/* store tv->tv_sec */
-	ltr	%r1,%r1
-	m	%r0,12f-6b(%r5)
-	jnm	9f
-	al	%r0,12f-6b(%r5)
-9:	srl	%r0,6
-	st	%r0,4(%r2)			/* store tv->tv_usec */
-10:	slr	%r2,%r2
-	ahi	%r15,16
-	CFI_ADJUST_CFA_OFFSET -16
-	CFI_RESTORE 15
-	br	%r14
-	CFI_ENDPROC
-11:	.long	1000000000
-12:	.long	274877907
-13:	.long	_vdso_data - 0b
-	.size	__kernel_gettimeofday,.-__kernel_gettimeofday

arch/s390/kernel/vdso32/note.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
- * Here we can supply some information useful to userland.
- */
-
-#include <linux/uts.h>
-#include <linux/version.h>
-#include <linux/elfnote.h>
-
-ELFNOTE_START(Linux, 0, "a")
-	.long LINUX_VERSION_CODE
-ELFNOTE_END

arch/s390/kernel/vdso32/vdso32.lds.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * This is the infamous ld script for the 32 bits vdso
- * library
- */
-
-#include <asm/page.h>
-#include <asm/vdso.h>
-
-OUTPUT_FORMAT("elf32-s390", "elf32-s390", "elf32-s390")
-OUTPUT_ARCH(s390:31-bit)
-ENTRY(_start)
-
-SECTIONS
-{
-	. = VDSO32_LBASE + SIZEOF_HEADERS;
-
-	.hash		: { *(.hash) }			:text
-	.gnu.hash	: { *(.gnu.hash) }
-	.dynsym		: { *(.dynsym) }
-	.dynstr		: { *(.dynstr) }
-	.gnu.version	: { *(.gnu.version) }
-	.gnu.version_d	: { *(.gnu.version_d) }
-	.gnu.version_r	: { *(.gnu.version_r) }
-
-	.note		: { *(.note.*) }		:text	:note
-
-	. = ALIGN(16);
-	.text		: {
-		*(.text .stub .text.* .gnu.linkonce.t.*)
-	} :text
-	PROVIDE(__etext = .);
-	PROVIDE(_etext = .);
-	PROVIDE(etext = .);
-
-	/*
-	 * Other stuff is appended to the text segment:
-	 */
-	.rodata		: { *(.rodata .rodata.* .gnu.linkonce.r.*) }
-	.rodata1	: { *(.rodata1) }
-
-	.dynamic	: { *(.dynamic) }		:text	:dynamic
-
-	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
-	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
-	.gcc_except_table : { *(.gcc_except_table .gcc_except_table.*) }
-
-	.rela.dyn ALIGN(8) : { *(.rela.dyn) }
-	.got ALIGN(8)	: { *(.got .toc) }
-
-	_end = .;
-	PROVIDE(end = .);
-
-	/*
-	 * Stabs debugging sections are here too.
-	 */
-	.stab	       0 : { *(.stab) }
-	.stabstr       0 : { *(.stabstr) }
-	.stab.excl     0 : { *(.stab.excl) }
-	.stab.exclstr  0 : { *(.stab.exclstr) }
-	.stab.index    0 : { *(.stab.index) }
-	.stab.indexstr 0 : { *(.stab.indexstr) }
-	.comment       0 : { *(.comment) }
-
-	/*
-	 * DWARF debug sections.
-	 * Symbols in the DWARF debugging sections are relative to the
-	 * beginning of the section so we begin them at 0.
-	 */
-	/* DWARF 1 */
-	.debug		0 : { *(.debug) }
-	.line		0 : { *(.line) }
-	/* GNU DWARF 1 extensions */
-	.debug_srcinfo	0 : { *(.debug_srcinfo) }
-	.debug_sfnames	0 : { *(.debug_sfnames) }
-	/* DWARF 1.1 and DWARF 2 */
-	.debug_aranges	0 : { *(.debug_aranges) }
-	.debug_pubnames 0 : { *(.debug_pubnames) }
-	/* DWARF 2 */
-	.debug_info	0 : { *(.debug_info .gnu.linkonce.wi.*) }
-	.debug_abbrev	0 : { *(.debug_abbrev) }
-	.debug_line	0 : { *(.debug_line) }
-	.debug_frame	0 : { *(.debug_frame) }
-	.debug_str	0 : { *(.debug_str) }
-	.debug_loc	0 : { *(.debug_loc) }
-	.debug_macinfo	0 : { *(.debug_macinfo) }
-	/* SGI/MIPS DWARF 2 extensions */
-	.debug_weaknames 0 : { *(.debug_weaknames) }
-	.debug_funcnames 0 : { *(.debug_funcnames) }
-	.debug_typenames 0 : { *(.debug_typenames) }
-	.debug_varnames  0 : { *(.debug_varnames) }
-	/* DWARF 3 */
-	.debug_pubtypes 0 : { *(.debug_pubtypes) }
-	.debug_ranges	0 : { *(.debug_ranges) }
-	.gnu.attributes 0 : { KEEP (*(.gnu.attributes)) }
-
-	. = ALIGN(PAGE_SIZE);
-	PROVIDE(_vdso_data = .);
-
-	/DISCARD/	: {
-		*(.note.GNU-stack)
-		*(.branch_lt)
-		*(.data .data.* .gnu.linkonce.d.* .sdata*)
-		*(.bss .sbss .dynbss .dynsbss)
-	}
-}
-
-/*
- * Very old versions of ld do not recognize this name token; use the constant.
- */
-#define PT_GNU_EH_FRAME	0x6474e550
-
-/*
- * We must supply the ELF program headers explicitly to get just one
- * PT_LOAD segment, and set the flags explicitly to make segments read-only.
- */
-PHDRS
-{
-	text		PT_LOAD FILEHDR PHDRS FLAGS(5);	/* PF_R|PF_X */
-	dynamic		PT_DYNAMIC FLAGS(4);		/* PF_R */
-	note		PT_NOTE FLAGS(4);		/* PF_R */
-	eh_frame_hdr	PT_GNU_EH_FRAME;
-}
-
-/*
- * This controls what symbols we export from the DSO.
- */
-VERSION
-{
-	VDSO_VERSION_STRING {
-	global:
-		/*
-		 * Has to be there for the kernel to find
-		 */
-		__kernel_gettimeofday;
-		__kernel_clock_gettime;
-		__kernel_clock_getres;
-		__kernel_getcpu;
-
-	local: *;
-	};
-}

arch/s390/kernel/vdso32/vdso32_wrapper.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/init.h>
-#include <linux/linkage.h>
-#include <asm/page.h>
-
-	__PAGE_ALIGNED_DATA
-
-	.globl vdso32_start, vdso32_end
-	.balign PAGE_SIZE
-vdso32_start:
-	.incbin "arch/s390/kernel/vdso32/vdso32.so"
-	.balign PAGE_SIZE
-vdso32_end:
-
-	.previous

arch/s390/kernel/vdso64/getcpu.S

···
 	.type  __kernel_getcpu,@function
 __kernel_getcpu:
 	CFI_STARTPROC
-	la	%r4,0
 	sacf	256
-	l	%r5,__VDSO_CPU_NR(%r4)
-	l	%r4,__VDSO_NODE_ID(%r4)
+	lm	%r4,%r5,__VDSO_GETCPU_VAL(%r0)
 	sacf	0
 	ltgr	%r2,%r2
 	jz	2f

arch/s390/lib/Makefile

···
 # Instrumenting memory accesses to __user data (in different address space)
 # produce false positives
 KASAN_SANITIZE_uaccess.o := n
+
+obj-$(CONFIG_S390_UNWIND_SELFTEST) += test_unwind.o
+CFLAGS_test_unwind.o += -fno-optimize-sibling-calls

arch/s390/lib/test_unwind.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test module for unwind_for_each_frame
+ */
+
+#define pr_fmt(fmt) "test_unwind: " fmt
+#include <asm/unwind.h>
+#include <linux/completion.h>
+#include <linux/kallsyms.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/kprobes.h>
+#include <linux/wait.h>
+#include <asm/irq.h>
+#include <asm/delay.h>
+
+#define BT_BUF_SIZE (PAGE_SIZE * 4)
+
+/*
+ * To avoid printk line limit split backtrace by lines
+ */
+static void print_backtrace(char *bt)
+{
+	char *p;
+
+	while (true) {
+		p = strsep(&bt, "\n");
+		if (!p)
+			break;
+		pr_err("%s\n", p);
+	}
+}
+
+/*
+ * Calls unwind_for_each_frame(task, regs, sp) and verifies that the result
+ * contains unwindme_func2 followed by unwindme_func1.
+ */
+static noinline int test_unwind(struct task_struct *task, struct pt_regs *regs,
+				unsigned long sp)
+{
+	int frame_count, prev_is_func2, seen_func2_func1;
+	const int max_frames = 128;
+	struct unwind_state state;
+	size_t bt_pos = 0;
+	int ret = 0;
+	char *bt;
+
+	bt = kmalloc(BT_BUF_SIZE, GFP_ATOMIC);
+	if (!bt) {
+		pr_err("failed to allocate backtrace buffer\n");
+		return -ENOMEM;
+	}
+	/* Unwind. */
+	frame_count = 0;
+	prev_is_func2 = 0;
+	seen_func2_func1 = 0;
+	unwind_for_each_frame(&state, task, regs, sp) {
+		unsigned long addr = unwind_get_return_address(&state);
+		char sym[KSYM_SYMBOL_LEN];
+
+		if (frame_count++ == max_frames)
+			break;
+		if (state.reliable && !addr) {
+			pr_err("unwind state reliable but addr is 0\n");
+			return -EINVAL;
+		}
+		sprint_symbol(sym, addr);
+		if (bt_pos < BT_BUF_SIZE) {
+			bt_pos += snprintf(bt + bt_pos, BT_BUF_SIZE - bt_pos,
+					   state.reliable ? " [%-7s%px] %pSR\n" :
+							    "([%-7s%px] %pSR)\n",
+					   stack_type_name(state.stack_info.type),
+					   (void *)state.sp, (void *)state.ip);
+			if (bt_pos >= BT_BUF_SIZE)
+				pr_err("backtrace buffer is too small\n");
+		}
+		frame_count += 1;
+		if (prev_is_func2 && str_has_prefix(sym, "unwindme_func1"))
+			seen_func2_func1 = 1;
+		prev_is_func2 = str_has_prefix(sym, "unwindme_func2");
+	}
+
+	/* Check the results. */
+	if (unwind_error(&state)) {
+		pr_err("unwind error\n");
+		ret = -EINVAL;
+	}
+	if (!seen_func2_func1) {
+		pr_err("unwindme_func2 and unwindme_func1 not found\n");
+		ret = -EINVAL;
+	}
+	if (frame_count == max_frames) {
+		pr_err("Maximum number of frames exceeded\n");
+		ret = -EINVAL;
+	}
+	if (ret)
+		print_backtrace(bt);
+	kfree(bt);
+	return ret;
+}
+
+/* State of the task being unwound. */
+struct unwindme {
+	int flags;
+	int ret;
+	struct task_struct *task;
+	struct completion task_ready;
+	wait_queue_head_t task_wq;
+	unsigned long sp;
+};
+
+static struct unwindme *unwindme;
+
+/* Values of unwindme.flags. */
+#define UWM_DEFAULT		0x0
+#define UWM_THREAD		0x1	/* Unwind a separate task. */
+#define UWM_REGS		0x2	/* Pass regs to test_unwind(). */
+#define UWM_SP			0x4	/* Pass sp to test_unwind(). */
+#define UWM_CALLER		0x8	/* Unwind starting from caller. */
+#define UWM_SWITCH_STACK	0x10	/* Use CALL_ON_STACK. */
+#define UWM_IRQ			0x20	/* Unwind from irq context. */
+#define UWM_PGM			0x40	/* Unwind from program check handler. */
+
+static __always_inline unsigned long get_psw_addr(void)
+{
+	unsigned long psw_addr;
+
+	asm volatile(
+		"basr	%[psw_addr],0\n"
+		: [psw_addr] "=d" (psw_addr));
+	return psw_addr;
+}
+
+#ifdef CONFIG_KPROBES
+static int pgm_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct unwindme *u = unwindme;
+
+	u->ret = test_unwind(NULL, (u->flags & UWM_REGS) ? regs : NULL,
+			     (u->flags & UWM_SP) ? u->sp : 0);
+	return 0;
+}
+#endif
+
+/* This function may or may not appear in the backtrace. */
+static noinline int unwindme_func4(struct unwindme *u)
+{
+	if (!(u->flags & UWM_CALLER))
+		u->sp = current_frame_address();
+	if (u->flags & UWM_THREAD) {
+		complete(&u->task_ready);
+		wait_event(u->task_wq, kthread_should_park());
+		kthread_parkme();
+		return 0;
+#ifdef CONFIG_KPROBES
+	} else if (u->flags & UWM_PGM) {
+		struct kprobe kp;
+		int ret;
+
+		unwindme = u;
+		memset(&kp, 0, sizeof(kp));
+		kp.symbol_name = "do_report_trap";
+		kp.pre_handler = pgm_pre_handler;
+		ret = register_kprobe(&kp);
+		if (ret < 0) {
+			pr_err("register_kprobe failed %d\n", ret);
+			return -EINVAL;
+		}
+
+		/*
+		 * trigger specification exception
+		 */
+		asm volatile(
+			"	mvcl	%%r1,%%r1\n"
+			"0:	nopr	%%r7\n"
+			EX_TABLE(0b, 0b)
+			:);
+
+		unregister_kprobe(&kp);
+		unwindme = NULL;
+		return u->ret;
+#endif
+	} else {
+		struct pt_regs regs;
+
+		memset(&regs, 0, sizeof(regs));
+		regs.psw.addr = get_psw_addr();
+		regs.gprs[15] = current_stack_pointer();
+		return test_unwind(NULL,
+				   (u->flags & UWM_REGS) ? &regs : NULL,
+				   (u->flags & UWM_SP) ? u->sp : 0);
+	}
+}
+
+/* This function may or may not appear in the backtrace. */
+static noinline int unwindme_func3(struct unwindme *u)
+{
+	u->sp = current_frame_address();
+	return unwindme_func4(u);
+}
+
+/* This function must appear in the backtrace. */
+static noinline int unwindme_func2(struct unwindme *u)
+{
+	int rc;
+
+	if (u->flags & UWM_SWITCH_STACK) {
+		preempt_disable();
+		rc = CALL_ON_STACK(unwindme_func3, S390_lowcore.nodat_stack, 1, u);
+		preempt_enable();
+		return rc;
+	} else {
+		return unwindme_func3(u);
+	}
+}
+
+/* This function must follow unwindme_func2 in the backtrace. */
+static noinline int unwindme_func1(void *u)
+{
+	return unwindme_func2((struct unwindme *)u);
+}
+
+static void unwindme_irq_handler(struct ext_code ext_code,
+				       unsigned int param32,
+				       unsigned long param64)
+{
+	struct unwindme *u = READ_ONCE(unwindme);
+
+	if (u && u->task == current) {
+		unwindme = NULL;
+		u->task = NULL;
+		u->ret = unwindme_func1(u);
+	}
+}
+
+static int test_unwind_irq(struct unwindme *u)
+{
+	preempt_disable();
+	if (register_external_irq(EXT_IRQ_CLK_COMP, unwindme_irq_handler)) {
+		pr_info("Couldn't reqister external interrupt handler");
+		return -1;
+	}
+	u->task = current;
+	unwindme = u;
+	udelay(1);
+	unregister_external_irq(EXT_IRQ_CLK_COMP, unwindme_irq_handler);
+	preempt_enable();
+	return u->ret;
+}
+
+/* Spawns a task and passes it to test_unwind(). */
+static int test_unwind_task(struct unwindme *u)
+{
+	struct task_struct *task;
+	int ret;
+
+	/* Initialize thread-related fields. */
+	init_completion(&u->task_ready);
+	init_waitqueue_head(&u->task_wq);
+
+	/*
+	 * Start the task and wait until it reaches unwindme_func4() and sleeps
+	 * in (task_ready, unwind_done] range.
+	 */
+	task = kthread_run(unwindme_func1, u, "%s", __func__);
+	if (IS_ERR(task)) {
+		pr_err("kthread_run() failed\n");
+		return PTR_ERR(task);
+	}
+	/*
+	 * Make sure task reaches unwindme_func4 before parking it,
+	 * we might park it before kthread function has been executed otherwise
+	 */
+	wait_for_completion(&u->task_ready);
+	kthread_park(task);
+	/* Unwind. */
+	ret = test_unwind(task, NULL, (u->flags & UWM_SP) ? u->sp : 0);
+	kthread_stop(task);
+	return ret;
+}
+
+static int test_unwind_flags(int flags)
+{
+	struct unwindme u;
+
+	u.flags = flags;
+	if (u.flags & UWM_THREAD)
+		return test_unwind_task(&u);
+	else if (u.flags & UWM_IRQ)
+		return test_unwind_irq(&u);
+	else
+		return unwindme_func1(&u);
+}
+
+static int test_unwind_init(void)
+{
+	int ret = 0;
+
+#define TEST(flags)							\
+do {									\
+	pr_info("[ RUN      ] " #flags "\n");				\
+	if (!test_unwind_flags((flags))) {				\
+		pr_info("[       OK ] " #flags "\n");			\
+	} else {							\
+		pr_err("[  FAILED  ] " #flags "\n");			\
+		ret = -EINVAL;						\
+	}								\
+} while (0)
+
+	TEST(UWM_DEFAULT);
+	TEST(UWM_SP);
+	TEST(UWM_REGS);
+	TEST(UWM_SWITCH_STACK);
+	TEST(UWM_SP | UWM_REGS);
+	TEST(UWM_CALLER | UWM_SP);
+	TEST(UWM_CALLER | UWM_SP | UWM_REGS);
+	TEST(UWM_CALLER | UWM_SP | UWM_REGS | UWM_SWITCH_STACK);
+	TEST(UWM_THREAD);
+	TEST(UWM_THREAD | UWM_SP);
+	TEST(UWM_THREAD | UWM_CALLER | UWM_SP);
+	TEST(UWM_IRQ);
+	TEST(UWM_IRQ | UWM_SWITCH_STACK);
+	TEST(UWM_IRQ | UWM_SP);
+	TEST(UWM_IRQ | UWM_REGS);
+	TEST(UWM_IRQ | UWM_SP | UWM_REGS);
+	TEST(UWM_IRQ | UWM_CALLER | UWM_SP);
+	TEST(UWM_IRQ | UWM_CALLER | UWM_SP | UWM_REGS);
+	TEST(UWM_IRQ | UWM_CALLER | UWM_SP | UWM_REGS | UWM_SWITCH_STACK);
+#ifdef CONFIG_KPROBES
+	TEST(UWM_PGM);
+	TEST(UWM_PGM | UWM_SP);
+	TEST(UWM_PGM | UWM_REGS);
+	TEST(UWM_PGM | UWM_SP | UWM_REGS);
+#endif
+#undef TEST
+
+	return ret;
+}
+
+static void test_unwind_exit(void)
+{
+}
+
+module_init(test_unwind_init);
+module_exit(test_unwind_exit);
+MODULE_LICENSE("GPL");

arch/s390/mm/maccess.c

···
  */
 int memcpy_real(void *dest, void *src, size_t count)
 {
-	if (S390_lowcore.nodat_stack != 0)
-		return CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack,
-				     3, dest, src, count);
+	int rc;
+
+	if (S390_lowcore.nodat_stack != 0) {
+		preempt_disable();
+		rc = CALL_ON_STACK(_memcpy_real, S390_lowcore.nodat_stack, 3,
+				   dest, src, count);
+		preempt_enable();
+		return rc;
+	}
 	/*
 	 * This is a really early memcpy_real call, the stacks are
 	 * not set up yet. Just call _memcpy_real on the early boot

arch/s390/pci/pci.c

···
 #include <linux/seq_file.h>
 #include <linux/jump_label.h>
 #include <linux/pci.h>
+#include <linux/printk.h>
 
 #include <asm/isc.h>
 #include <asm/airq.h>
···
 		spin_lock(&zpci_domain_lock);
 		if (test_bit(zdev->domain, zpci_domain)) {
 			spin_unlock(&zpci_domain_lock);
+			pr_err("Adding PCI function %08x failed because domain %04x is already assigned\n",
+				zdev->fid, zdev->domain);
 			return -EEXIST;
 		}
 		set_bit(zdev->domain, zpci_domain);
···
 	zdev->domain = find_first_zero_bit(zpci_domain, ZPCI_NR_DEVICES);
 	if (zdev->domain == ZPCI_NR_DEVICES) {
 		spin_unlock(&zpci_domain_lock);
+		pr_err("Adding PCI function %08x failed because the configured limit of %d is reached\n",
+			zdev->fid, ZPCI_NR_DEVICES);
 		return -ENOSPC;
 	}
 	set_bit(zdev->domain, zpci_domain);

drivers/s390/crypto/zcrypt_error.h

···
 #define REP82_ERROR_EVEN_MOD_IN_OPND	    0x85
 #define REP82_ERROR_RESERVED_FIELD	    0x88
 #define REP82_ERROR_INVALID_DOMAIN_PENDING  0x8A
+#define REP82_ERROR_FILTERED_BY_HYPERVISOR  0x8B
 #define REP82_ERROR_TRANSPORT_FAIL	    0x90
 #define REP82_ERROR_PACKET_TRUNCATED	    0xA0
 #define REP82_ERROR_ZERO_BUFFER_LEN	    0xB0
···
 	case REP82_ERROR_INVALID_DOMAIN_PRECHECK:
 	case REP82_ERROR_INVALID_DOMAIN_PENDING:
 	case REP82_ERROR_INVALID_SPECIAL_CMD:
+	case REP82_ERROR_FILTERED_BY_HYPERVISOR:
 	//   REP88_ERROR_INVALID_KEY		// '82' CEX2A
 	//   REP88_ERROR_OPERAND		// '84' CEX2A
 	//   REP88_ERROR_OPERAND_EVEN_MOD	// '85' CEX2A